Coolant motor fan drive

ABSTRACT

The control of the coolant flow is accomplished through valving or by adjusting the pumping speed of a water pump and a water motor, or a combination of all three elements. During normal operation, where engine cooling is not required, the speed control coupling maintains a slow and constant water pump speed at all engine-operating speeds. The valve is maintained to stop coolant flow from entering the radiator while allowing coolant to flow through a heater. If engine cooling is required, the valve is actuated such that coolant is circulated to the engine and through the radiator. If air conditioning is required, the speed control coupling simply increases the water pump speed and the fan speed while the valve is set to bypass coolant flow to the engine. If air conditioning and engine cooling are required, the valve is actuated to allow coolant flow to the engine.

TECHNICAL FIELD

The present invention relates generally to an engine cooling systems andmore specifically to a coolant motor fan drive.

BACKGROUND ART

Generally, a water-cooling type engine of a vehicle includes a coolingsystem provided with a radiator and a flow control valve. The radiatoris located in an engine coolant circuit for cooling the coolant. Theflow control valve regulates the flow of the coolant that passes throughthe radiator. The flow control valve is controlled to change the coolantflow in the radiator (hereafter, “the radiator flow”). This adjusts thetemperature of the coolant, which cools the engine.

The flow control valve is fully closed to minimize the radiator flowwhen the coolant temperature is relatively low. In contrast, when thecoolant temperature is relatively high, the flow control valve is fullyopened to maximize the radiator flow. Otherwise, a feedback controlprocedure is performed to vary the opening size of the flow controlvalve (the radiator flow) depending on the coolant temperature, suchthat the coolant temperature seeks a predetermined target.

To cool the coolant within the radiator, a cooling fan is mounted inclose proximity to the radiator to providing cooling airflow to theradiator. Preferably, the cooling fan is coupled to the water pump.

However, many engine-cooling applications do not allow for conventionalmounting of an engine-cooling fan on a water pump. For example, frontwheel drive systems, or systems where the centerline of the water pumpis not covered by the radiator, use electric motor driven systems orhydraulically driven fans to control the temperature of the coolantleaving the radiator. These systems are costly and inefficient.

Another potential issue related to cooling system performance iselectrical power usage. As automotive manufacturers continue tointroduce optional electrical equipment on automobiles, electricaldemands within the vehicle correspondingly are increased. Further,customer demands for increased horsepower and towing capacity createadditional demands on electrical systems. These extra demands placeincreased burdens on cooling systems to cool the engine compartmentwithout significantly increasing electrical demand.

It is thus highly desirable to provide a way to cool an engine using anexisting source of power that is economical and efficient.

SUMMARY OF THE INVENTION

The present invention utilizes an existing source of power, the coolantflow, and an economical water motor to drive an engine-cooling fanmounted to a water pump.

The control of the coolant flow is accomplished through valving or byadjusting the impeller rotational speed of the water pump, or acombination of both. Since the duty cycle of the cooling system is low,a clutch or recirculation path can be used when coolant flow or airflowrequirements are low, thereby saving energy and providing an alternativecontrol method.

During normal operation, where engine cooling is not required, the speedcontrol coupling maintains a slow and constant water pump speed at allengine-operating speeds. The valve is maintained in a closed positionand stops coolant flow from entering the radiator. Coolant is directedinstead through a heater to maintain circulation and control hot spotsand allow rapid engine warm-up.

If engine cooling is required, the valve is actuated and coolant iscirculated to the engine and through the radiator and water motor at lowpump speeds. The water motor and coupled fan are then actuated, therebycooling the coolant as it flows through the radiator. If coolingrequirements increase, the water pump is switched to high speed and thesystem operates at maximum heat rejection capacity.

When airflow for the air conditioner condenser is needed, the speedcontrol coupling simply increases the water pump speed, and hence thefan speed. This can be controlled from air conditioner head pressure orsimply actuated with the air conditioner compressor. Pilot pressure atthe valve can direct coolant flow back to the pump by passing the engineand avoiding overcooling.

If both cooling and air conditioning are required, the pump speedcoupling and the valve are both actuated to drive the fan at maximumspeed and pump all the coolant through the engine.

In alternative preferred embodiments, because of the huge rpm range ofsome motors, a dual stage pump is used as either the water pump, watermotor, or both the water pump and water motor. The dual stage pumpallows for a more varying response between engine speed and pump/fanoutput.

Other objects and advantages of the present invention will becomeapparent upon the following detailed description and appended claims,and upon reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an engine cooling system according to apreferred embodiment of the present invention having a valve in a closedposition;

FIG. 2 is a perspective view of FIG. 1 in which the valve is in an openposition;

FIG. 3 is a perspective view of FIG. 1 in which the valve is in a thirdposition;

FIG. 4 is a perspective view of an engine cooling system according toanother preferred embodiment of the present invention;

FIG. 5 is a perspective view of an engine cooling system according toanother preferred embodiment of the present invention; and

FIG. 6 is a perspective view of an engine cooling system according toanother preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1-3, a perspective view of a cooling system usedto cool an engine 22 of a vehicle 10 in one preferred embodiment isgenerally designated as 20. The engine 22 has a crankshaft 24 coupled toa crankshaft pulley 26. The crankshaft pulley 26 is rotatably coupled toa water pump 28 via a pump control coupling 30, which is coupled to thecrankshaft pulley 26 via a belt 32. The cooling system 20 also has aheater element 47 used to increase the temperature of the engine 22 asdesired and to provide heated air to the passenger cabin of the vehicleas desired by a vehicle user 75. The cooling system 20 also has anair-conditioning unit 69 providing cooling airflow to the passengercabin as requested by the user 75.

The location of the user 75 relative to the heater element 47 and airconditioner 69, as shown in FIGS. 1-6 of the present invention, ismerely for illustrative purpose only, and is not representative of theiractual positioning within the vehicle 10.

The cooling system has a series of coolant lines 36, 44, 48 used tofluidically couple the various components of the cooling system 20 tomaintain the engine 22 at an optimal operating temperature at a givenengine speed while maintaining the passenger cabin at a desiredtemperature for the user 75.

The water pump 28 is fluidically coupled to a heater element 47 and tothe engine 22 through a first coolant line 44. A second coolant line 36is fluidically coupled to the first coolant line 44 at a first end,terminating at a first junction 51. The second coolant line is alsofluidically coupled at its opposite end to the first coolant line 44,terminating at a second junction 52.

A water motor 38 having an attached fan 40 is fluidically coupled withthe second coolant line 36 between radiator 34 and water pump 28. Thefan 40 is coupled in such a way as to provide cooling airflow to theradiator 34 when rotating. A valve 60 coupled to the second coolant line36 is located between the radiator 34 and second junction 52.

A third coolant line 48 is fluidically coupled to the second coolantline 36 through the valve 60 at one end and to the first coolant line 44at junction 50 at a second end such that the third coolant line bypassesthe engine 22.

Thus, the coolant lines 36, 44, 48 form a continuous closed loop andcontain a quantity of coolant 80 there within that is used to warm up orcool down the engine 22 to maintain the engine 22 is a desiredtemperature operating zone.

The pump control coupling 30, also known as a speed control coupling 30,preferably takes the form of an on/off electric clutch or anelectrically controlled viscous clutch well known to those of ordinaryskill in the art. As such, the amount of rotational response of thecoupled water pump 28 is controlled as a function of the degree ofengagement of the pump control coupling 30.

The cooling system also has an air conditioner 69 including a condenser71 and a compressor 73. The air conditioner 69 is controlled by a user75 and is also electrically coupled to the controller 70. The condenser71 is capable of receiving cooling airflow (ram flow) from outside airas the vehicle is moving.

The valve 60, heater element 47, air conditioner 69, and pump controlcoupling 30 are all electrically coupled to and controlled by acontroller 70. In addition, at least one temperature sensor 77 iscoupled to the controller 70 and measures the temperature of the engine22 during operating conditions.

While one temperature sensor 77 is shown as being coupled to the engine22 in FIGS. 1-3, the number and location of the temperature sensor 77could vary greatly within cooling systems 20 and still accuratelymeasure the engine operating temperature. For example, the temperaturesensor 77 could be alternatively mounted to cooling line 44 between theengine 22 and junction 50. Further, multiple temperature sensors 77located throughout the cooling system could all be coupled to thecontroller and used to accurately measure engine operating temperature.Thus, the number and location of temperature sensors 77 is not meant tobe limited to that illustrated in FIGS. 1-3.

In warm-up conditions, as displayed in FIG. 1, wherein the engine 22 isoperating below a desired operating temperature (as measured by thetemperature sensor 77), the controller 70 will direct the valve 60closed and the speed control coupling 30 to maintain a slow and constantwater pump 28 speed. Thus coolant 80 will thus flow from the water pump28, through first coolant line 44 and the heater element 47 and theengine 22, therein returning to the pump 28. This coolant 80 is warmedas is flow through the jeater element 47 to allow for rapid engine 22warm-ups. However, because the coolant 80 is constantly flowing throughthe first coolant line 44, hot spots are eliminated on the engine 22.The controller 70 can also control the amount of heat exchanged to thecoolant 80 within the heater element 47 by simply increasing ordecreasing the temperature of the heater element 47 itself, or byslightly altering the rotational speed of the speed control coupling 30(and water pump 28), or by a combination of pumping speed control andheater control.

As engine operating temperatures increase closer to, but still below, adesired engine operating temperature, the controller 70 will direct thespeed coupling 30 to increase its rotational speed, therein increasingthe rotational rate of the water pump 28 in response, which in turnincreases the flow rate of coolant 80 as it flows through the water pump28 and heater element 47. Thus, coolant 80 flows through the heaterelement 47 at a higher flow rate, which translates into less heattransfer per unit coolant 80. Thus, the engine 22 will continue towarm-up, but at a lesser relative rate.

At the desired engine operating temperature, as shown in FIG. 2, thecontroller 70 will direct the valve 60 to open, therein allowing coolant80 to flow through the second coolant line 36 from the first junction 51to the second junction 52. This coolant flow engages water motor 38 todrive fan 40, which provides cooling airflow to the radiator 34. Thus,as coolant 80 flows through the radiator 34, the coolant 80 is cooled inproportion to the coolant flow rate through the radiator and inproportion to the fan 40 rotational rate, which provides cooling airflow to the radiator 34 as the fan 40 is rotated by the water motor 38.

At the same time, coolant 80 flows from pump 28 and through the firstcoolant line 44. The cooler coolant 80 from second coolant line 36merges with the warmer coolant 80 from the first coolant line 44 atjunction 52 and continues to flows through the engine 22. Thus, thecooler coolant 80 flowing through the second coolant line 36 and thewarmer coolant 80 flowing through the first coolant line 44 merge atjunction 52 and flow together back through the engine 22 and line 44 topump 28.

If engine temperatures increase over a desired engine operatingtemperature, the controller 70 simply directs the speed controller 30 toincrease the water pump 28 speed, while maintaining the valve 60 in anactuated or open position. This in turn increases the water motor 38speed, and hence the fan 40 rotational speed. The net effect is thatmore cooling airflow is directed to the radiator 34 from the fan 40,which decreases the coolant 80 temperature further. At the same time,coolant 80 flowing through line 44 and heater element 47 is not warmedas much as at slower pump speeds. Thus, as the pump speed 28 increases,merged coolant 80 flowing from junction 52 to engine 22 is cooler thanat lower pump speeds, which in turn aids in cooling the engine 22 as themerged coolant 80 returns to the water pump 28 through coolant line 44.

When the user 75 desires air conditioning to cool the cabin area of thevehicle, the user 75 simply turns on the air conditioning 69 within thecabin of the vehicle. In order to accommodate this request, as shown inFIG. 3, cooling airflow for the air conditioning condenser 71 is neededto condense freon contained within the condenser 71 from a gas to aliquid. Pilot pressure generated within the compressor 73 as the airconditioner 69 is activated actuates the valve 60 to move from either aclosed position or an open position to a second open position such thatcoolant may flow from line 36 through line 48 and back to the water pump28. At the same time, coolant 80 flow from the second coolant line 36between the valve 60 and junction 52 and to the engine 22 is prevented.Thus, coolant 80 flows through water motor 38, therein activating thefan 40 to provide additional cooling airflow to the radiator 34 andcondenser 71. The coolant 80 exits the radiator 34 and returns to thewater pump 28 through valve 60, third coolant line 48, junction 50, andfirst coolant line 44.

If additional cooling is desired, especially at idle conditions, thecontroller 70 will direct the speed coupling 30 to increase itsrotational speed at a given engine speed, and hence the water pump 28speed, which in turn increases the pumping speed of water motor 38 androtational speed of the fan 40. This further increases airflow from thefan 40 to the air conditioner condenser 71.

If both engine cooling, as sensed by sensor 77, and air conditioning 69is requested by the user 75, the controller 70 actuates the pump speedcoupling 30 to produce maximum pumping action and directs the valve 60from the second open position (or closed position, depending upon thepilot pressure within the compressor 73) to the first open position toprovide coolant 80 flow back from the radiator 34 to the engine 22through second line 36 to junction 52. This drives the fan 40 at maximumspeed while allowing coolant 80 to pass through the line 36 and thejunction 52 to the engine 22.

FIGS. 4-6 illustrate three more preferred embodiments of the presentinvention that are essentially useful for vehicle cooling systems inwhich the engines that they cool have a high range of potential enginespeeds, especially as compared with idling conditions. For example, inFIG. 4, a dual stage water pump 128 is utilized in place of the singlestage water pump 28 of FIGS. 1-3. In FIG. 5, a dual stage water motor138 replaces the single stage water motor 38 of FIGS. 1-3. FIG. 6incorporates a dual stage water pump 128 and a dual stage water motor138.

A dual stage water pump 128, as shown in FIGS. 4 and 6, consists of apair of independently actuated pumps 129, 130 (i.e. stages) coupled tothe speed control coupling 30. Each pump 129, 130 is electricallycoupled to the controller 70. Depending upon the desired coolant flowrate, one or both pumps may be actuated. When both pumps 129, 130 areactuated, the coolant flow rate increases as compared with the use of asingle one of the two pumps. As such, the coolant flow rate can beadjusted stepwise in conjunction with the speed control coupling 30.

A dual stage water motor 138, as shown in FIGS. 5 and 6, consists of apair of independently actuated water motors 139, 140 (i.e. stages)coupled to the speed control coupling 30. Each pump 139, 140 iselectrically coupled to the controller 70. Depending upon the desiredcoolant 80 flow rate and fan 40 rotation rate, one or both pumps may beactuated. When both pumps 139, 140 are actuated, the coolant flow rateand fan 40 rotational rate increases as compared with the use of asingle one of the two pumps. As such, the temperature and coolant flowrate of coolant flowing through the second line 36 can be adjustedstepwise in conjunction with the speed control coupling 30. This allowsfor more precise control of temperature of the coolant entering theengine when the valve 60 is in an open position. This can lead toimproved fuel economy and emissions.

The dual stage nature of the water pump and water motor allows bothstages to be working in conditions where maximum coolant flow isrequired, such as in engine idle conditions in which the engine is abovethe desired operating temperature. However, when the vehicle is moving,or when the vehicle is below the desired operating temperature, one ofthe stages may be turned off.

In addition, the dual stage nature is especially useful in engineshaving a high variation of engine speeds. Thus, for example, when lowengine speeds are present, such as in engine idle, the water pump 128can be directed to only utilize a single stage. As engine speedsincrease, for example to 5000-6000 revolutions per minute (rpms), thesecond stage 130 may be activated. Thus, less horsepower is required todrive the speed coupling 30, and excess horsepower can be utilizedelsewhere in the engine, therein increasing engine performance in termsof available horsepower, emissions, and fuel economy. Additionally, lesselectrical energy is needed to control the speed coupling 30.

With respect to FIG. 4, in warm-up conditions, wherein the engine 22 isoperating below a desired operating temperature as measured by atemperature sensor 77, the controller 70 will direct the valve 60 closedand the speed control coupling 30 to maintain a slow and constant waterpump 128 speed. In warm-up conditions, only one stage of the dual stagewater pump 128 is on, therein limiting the coolant flow rate throughline 44 and the heater element 47 to provide maximum warming of thecoolant 80 within the heater element 47.

As engine operating temperatures increase closer to, but still below, adesired engine operating temperature, the controller 70 will direct thespeed coupling 30 to increase its rotational speed, therein increasingthe flow rate of coolant 80 through the water pump 128 and heaterelement 47. Alternatively, or in conjunction with increasing therotational speed of the speed coupling 30, the controller 70 will turnon the second stage of the water pump, therein increasing the coolant 80flow.

At the desired engine operating temperature, the controller 70 willdirect the valve 60 to open, therein allowing coolant 80 to flow throughsecond line 36 from the first junction 51 to the second junction 52.This engages water motor 38 to drive fan 40, which provides coolingairflow to the radiator 34. Thus, as coolant 80 flows through theradiator, the coolant is cooled. At the same time, coolant 80 flows frompump 128 and through first coolant line 44. The cooler coolant 80 fromthe second coolant line 36 merges with the warmer coolant 80 from thefirst coolant line 44 at junction 52. The merged coolant continues toflow through the first coolant line, 44 and back to the pump 128.

At the desired engine operating temperature, as the vehicle 10 ismoving, one or both stages of the dual stage water pump 128 is on,therein controlling the coolant flow rate through both lines 36, 44.However, during engine idle conditions, only one stage of the dual stagewater pump 128 is typically activated, therein decreasing the flow rateof coolant 80 through both lines 36, 44 to maintain the engine in adesired operating zone.

If engine temperatures increase over a desired engine operatingtemperature, the controller 70 simply directs the speed controller 30 toincrease the water pump 128 speed while maintaining the valve 60 in anactuated position. Alternatively, or in conjunction with this speedincrease, the controller 70 may actuate both stages of the water pump128. This in turn increases the water motor 38 speed, and hence the fan40 rotational speed. The net effect is that more cooling airflow isdirected to the radiator 34 from the fan 40, which decreases the coolant80 temperature further. Thus, as the pump speed 128 increases, coolantflowing from junction 52 is cooler than at lower pump speeds, which inturn aids in cooling the engine 22 as the coolant 80 returns to thewater pump 128 through coolant line 44.

When the user 75 desires air conditioning to cool the cabin area of thevehicle 10, he simply turns on the air conditioning 69 within the cabinof the vehicle 10. As described above, the increase in pilot pressureactuates the valve 60 to allow coolant 80 flowing through the secondcoolant line 36 to bypass the engine 22 through junction 52 and flowinstead through line 48 and back to the pump 128. The controller 70simply directs the speed controller 30 to increase the water pump 128speed, and hence the coolant flow, through the second coolant line 36and third coolant line 48. Alternatively, or in conjunction with thisspeed increase, the controller 70 actuates one or both stages of thedual action pump.

If additional cooling is desired, especially at idle conditions, thecontroller 70 will direct the speed coupling 30 to increase itsrotational speed and actuate dual stages, and hence the water pump 28speed, which in turn increases the water motor 38 and fan speed 40. Thisfurther increases airflow from the fan 40 to the air conditionercondenser 71.

If both engine cooling, as sensed by sensor 77, and air conditioning isrequested, the controller 70 actuates the pump speed coupling 30 toproduce maximum pumping action, utilizing both stages of the dual stagepump 128, and opens valve 60 to provide coolant flow back from theradiator 34 to the engine 22 through coolant line 36 and junction 52.This drives the fan 40 at maximum speed while allowing the cooledportion of the coolant 80 to pass through the engine 22.

With respect to FIG. 5, in warm-up conditions, wherein the engine 22 isoperating below a desired operating temperature as measured by atemperature sensor 77, the controller 70 will direct the valve 60 closedand the speed control coupling 30 to maintain a slow and constant waterpump 28 speed, therein limiting the coolant flow rate through line 44and the heater element 47 to provide maximum warming of the coolant 80within the heater element 47.

As engine operating temperatures increase closer to, but still below, adesired engine operating temperature, the controller 70 will direct thespeed coupling 30, and hence the water pump 28 rotational speed, thereinincreasing the flow rate of coolant 80 through the water pump 28 andheater element 47.

At the desired engine operating temperature, the controller 70 willdirect the valve 60 to open, therein allowing coolant 80 to flow throughsecond line 36 from the first junction 51 to the second junction 52.This engages the dual stage water motor 138 to drive fan 40, whichprovides cooling airflow to the radiator 34. Thus, as coolant 80 flowsthrough the radiator 34, the coolant 80 is cooled. At the same time,coolant 80 flows from pump 28 and through first coolant line 44. Thecooler coolant 80 from the second coolant line 36 merges with the warmercoolant 80 from the first coolant line 44 at junction 52. The mergedcoolant continues to flow through the first coolant line 44 and back tothe pump 28.

To precisely control the amount of cooling of the coolant occurring inthe radiator, the controller may direct on one or both stages 139, 140of the water motor. The rotational rate of the fan 40 is greater, andhence the amount of airflow to the radiator 34, at a given pump 28speed, when both stages 139, 140 are actuated. The incorporation of adual stage water motor 138 allows different cooling characteristics tobe achieved for coolant 80 returning to the engine 22 through junction52, hence the merged coolant will be cooler if both stages 139, 140 areactuated and slightly warmer if only one stage 139 is used.

If engine temperatures increase over a desired engine operatingtemperature, the controller 70 simply directs the speed controller 30 toincrease the water pump 28 speed while maintaining the valve 60 in anactuated position. Alternatively, or in conjunction with this speedincrease, the controller 70 may actuate both stages 139, 140 of thewater pump 128. This in turn increases the water motor 38 speed, andhence the fan 40 rotational speed, as compared with one stage 139 beingactuated. The net effect is that more cooling airflow is directed to theradiator 34 from the fan 40, which decreases the coolant 80 temperaturefurther. Thus, as the pump speed 28 increases, coolant flowing fromjunction 52 is cooler than at lower pump speeds, which in turn aids incooling the engine 22 as the coolant 80 returns to the water pump 128through coolant line 44.

When the user 75 desires air conditioning to cool the cabin area of thevehicle 10, he simply turns on the air conditioning 69 within the cabinof the vehicle 10. As described above, the increase in pilot pressureactuates the valve 60 to allow coolant 80 flowing through the secondcoolant line 36 to bypass the engine 22 through junction 52 and flowinstead through line 48 and back to the pump 128. The controller 70simply directs the speed controller 30 to increase the water pump 28speed, and hence the coolant flow, through the second coolant line 36and third coolant line 48.

If both engine cooling, as sensed by sensor 77, and air conditioning 69is requested, the controller 70 actuates the pump speed coupling 30 toproduce maximum pumping action by the pump 28, and opens valve 60 toprovide coolant flow back from the radiator 34 to the engine 22 throughcoolant line 36 and junction 52. The controller 70 will also direct oneor both stages 139, 140 of the water motor 138 to drive the drives thefan 40 at the desired rotational speed while allowing the cooled portionof the coolant 80 to pass through the engine 22, and not bypass theengine 22 through line 48.

With respect to FIG. 6, in warm-up conditions, wherein the engine 22 isoperating below a desired operating temperature as measured by atemperature sensor 77, the controller 70 will direct the valve 60 closedand the speed control coupling 30 to maintain a slow and constant waterpump 128 speed. In warm-up conditions, only one stage of the dual stagewater pump 128 is on, therein limiting the coolant flow rate throughline 44 and the heater element 47 to provide maximum warming of thecoolant 80 within the heater element 47.

As engine operating temperatures increase closer to, but still below, adesired engine operating temperature, the controller 70 will direct thespeed coupling 30 to increase its rotational speed, therein increasingthe flow rate of coolant 80 through the water pump 128 and heaterelement 47. Alternatively, or in conjunction with increasing therotational speed of the speed coupling 30, the controller 70 will turnon the second stage 130 of the water pump 128, therein increasing thecoolant 80 flow.

At the desired engine operating temperature, the controller 70 willdirect the valve 60 to open, therein allowing coolant 80 to flow throughsecond line 36 from the first junction 51 to the second junction 52.This engages water motor 138 to drive fan 40, which provides coolingairflow to the radiator 34. Thus, as coolant 80 flows through theradiator, the coolant 80 is cooled. At the same time, coolant 80 flowsfrom pump 128 and through first coolant line 44. The cooler coolant 80from the second coolant line 36 merges with the warmer coolant 80 fromthe first coolant line 44 at junction 52. The merged coolant continuesto flow through the first coolant line 44 and back to the pump 128.Depending upon the characteristics of the engine 22, one or both stages139, 140 of the water motor 138 may be actuated by the controller 70.

At the desired engine operating temperature, as the vehicle 10 ismoving, one or both stages of the dual stage water pump 128 is on,therein controlling the coolant flow rate through both lines 36, 44.However, during engine idle conditions, only one stage of the dual stagewater pump 128 is typically activated, therein decreasing the flow rateof coolant 80 through both lines 36, 44 to maintain the engine in adesired operating zone. Also, one or both stages 139, 140 of the watermotor are activated to further regulate the temperature of the coolant80 flowing through line 36 and back to the engine 22.

If engine temperatures increase over a desired engine operatingtemperature, the controller 70 simply directs the speed controller 30 toincrease the water pump 128 speed while maintaining the valve 60 in anactuated position. Alternatively, or in conjunction with this speedincrease, the controller 70 may actuate both stages 129, 130 of thewater pump 128. This in turn increases the water motor 138 speed, andhence the fan 40 rotational speed. The net effect is that more coolingairflow is directed to the radiator 34 from the fan 40, which decreasesthe coolant 80 temperature further. Thus, as the pump speed 128increases, coolant 80 flowing from junction 52 is cooler than at lowerpump speeds, which in turn aids in cooling the engine 22 as the coolant80 returns to the water pump 128 through coolant line 44. Typically,both stages 139, 140 of the dual stage water motor 138 will be actuatedby the controller 70 to provide maximum fan 40 rotational speed to coolthe coolant 80 as it flows through the radiator 34.

When the user 75 desires air conditioning to cool the cabin area of thevehicle 10, he simply turns on the air conditioning 69 within the cabinof the vehicle 10. As described above, the increase in pilot pressureactuates the valve 60 to allow coolant 80 flowing through the secondcoolant line 36 to bypass the engine 22 through junction 52 and flowinstead through line 48 and back to the pump 128. The controller 70simply directs the speed controller 30 to increase the water pump 128speed, and hence the coolant flow, through the second coolant line 36and third coolant line 48. Alternatively, or in conjunction with thisspeed increase, the controller 70 actuates one or both stages 129, 130of the dual action pump 128 and/or one or both stages 139, 140 of thewater motor 138.

If additional cooling is desired, especially at idle conditions, thecontroller 70 will direct the speed coupling 30 to increase itsrotational speed and actuate dual stages 129, 130 of the water pump 128,and hence the water pump 128 speed, which in turn increases the watermotor 138 and fan speed 40. This further increases airflow from the fan40 to the air conditioner condenser 71. Also, typical both stages 139,140 of the water motor are activated to further decrease the temperatureof the coolant 80 flowing through line 36 and back to the engine 22.

If both engine cooling, as sensed by sensor 77, and air conditioning 69are requested, the controller 70 actuates the pump speed coupling 30 toproduce maximum pumping action, utilizing both stages 129, 130 of thedual stage pump 128, and open valve 60 to provide coolant flow back fromthe radiator 34 to the engine 22 through coolant line 36 and junction52. Also, typically both stages 139, 140 of the water motor areactivated to provide maximum fan 40 rotational speed to further decreasethe temperature of the coolant 80 flowing through line 36 and back tothe engine 22.

While one particular embodiment of the invention have been shown anddescribed, numerous variations and alternative embodiments will occur tothose skilled in the art. Accordingly, it is intended that the inventionbe limited only in terms of the appended claims.

1. A cooling system for an engine, the cooling system comprising: afirst coolant line coupled to the engine; a heater element coupled tosaid first coolant line; a second coolant line fluidically coupled tosaid first coolant line at a first end and a second end, wherein saidfirst coolant line and said second coolant line form a continuous closedloop; a quantity of coolant contained within said continuous closedloop; a radiator fluidically coupled to said second coolant line betweensaid first end and said second end; a water pump fluidically coupledwithin said first coolant line and rotatably coupled to said engine; awater motor fluidically coupled to said second coolant line between saidfirst end and said second end; a fan coupled to said water motor,saidfan rotating to cool said radiator as a function of the flow rate ofsaid quantity of coolant through said water motor; a valve fluidicallycoupled to said second coolant line, said valve having an open positionand a closed position, said closed position preventing flow of saidquantity of coolant through said second coolant line and said openposition allowing flow of said quantity of coolant through said secondcoolant line; a pump control coupling coupled to said pump, said pumpcontrol coupling controlling the rotational rate of said water pump andsaid water pump impellers to pump said quantity of coolant through saidsecond coolant line; a belt coupled to said crankshaft pulley and saidpump control coupling; at least one temperature sensor capable ofmeasuring engine operating temperature; and a controller electricallycoupled to said valve and electrically coupled to said speed controlcoupling and electrically coupled to said at least one temperaturesensor, said controller controlling the actuation of said valve andcontrolling the rotational rate of said speed control coupling as afunction of said measured engine operating temperature.
 2. The coolingsystem of claim 1, wherein said water pump comprises a dual stage waterpump.
 3. The cooling system of claim 1, wherein said water motorcomprises a dual stage water motor.
 4. The cooling system of claim 1further comprising: a third coolant line fluidically coupled to saidfirst coolant line and said second coolant line, wherein said firstcoolant line, said second coolant line and said third coolant line forma continuous closed loop; an air conditioning unit coupled to saidcontroller, said air conditioning unit having a compressor, saidcompressor coupled near said fan and capable of receiving air flow fromsaid fan as said fan is rotated; wherein said compressor is coupled tosaid valve, wherein pilot pressure generated within said compressor whensaid air conditioner is actuated is capable of moving said valve to asecond open position, said second open position allowing coolant flowthrough said third coolant line while preventing coolant flow throughsaid second coolant line.
 5. The cooling system of claim 1, wherein saidspeed control coupling comprises an on/off clutch.
 6. The cooling systemof claim 1, wherein said speed control coupling comprises anelectronically controlled viscous coupling.
 7. A method for controllingthe temperature of an engine at a current engine speed, the methodcomprising: (a) providing a cooling system comprising: a first coolantline coupled to the engine; a heater element coupled to said firstcoolant line; a second coolant line fluidically coupled to said firstcoolant line at a first end and a second end; wherein said first coolantline and said second coolant line form a continuous closed loop; aquantity of coolant contained within said continuous closed loop; aradiator fluidically coupled to said second coolant line between saidfirst end and said second end; a water pump fluidically coupled withinsaid first coolant line and rotatably coupled to said engine; a watermotor fluidically coupled to said second coolant line between said firstend and said second end; a fan coupled to said water motor, said fanrotating to cool said radiator as a function of the flow rate of saidquantity of coolant through said water motor; a valve fluidicallycoupled to said second coolant line, said valve having an open positionand a closed position; a pump control coupling coupled to said pump,said pump control coupling controlling the rotational rate of said waterpump and said water pump impellers to pump said quantity of coolantthrough said second coolant line; a belt coupled to said crankshaftpulley and said pump control coupling; at least one temperature sensorcapable of measuring engine operating temperature; and a controllerelectrically coupled to said valve and electrically coupled to saidspeed control coupling and electrically coupled to said at least onetemperature sensor; (b) determining an engine operating temperature atthe current engine speed using said at least one temperature sensor; (c)determining a desired operating temperature for the engine at thecurrent engine speed; and (d) controlling the actuation of said valvebetween said closed position and said open position and controlling therotational rate of said speed control coupling using said controller tochange said engine operating temperature to said desired operatingtemperature at the current engine speed.
 8. The method of claim 7,wherein (d) further comprises controlling the rotational rate of saidspeed control coupling using said controller to change said engineoperating temperature to said desired operating temperature at thecurrent engine speed.
 9. The method of claim 7, wherein (d) controllingthe actuation comprises (d) decreasing said engine operating temperatureto said desired operating temperature by actuating said valve to saidopen position to allow coolant to flow through said second coolant line.10. The method of claim 8, wherein (d) controlling the actuationcomprises (d) decreasing said engine operating temperature to saiddesired operating temperature by increasing the rotational rate of saidspeed control coupling.
 11. The method of claim 8, wherein (d)controlling the actuation comprises: decreasing said engine-operatingtemperature to said desired operating temperature by actuating saidvalve to said open position to allow coolant to flow through said secondcoolant line; and increasing the rotational rate of said speed controlcoupling at the current engine speed.
 12. A method for controlling thetemperature of an engine at a current engine speed having an actuatedair-conditioning unit, the air-conditioning unit having a compressor anda condenser, the method comprising: (a) providing a cooling systemcomprising: a first coolant line coupled to the engine; a heater elementcoupled to said first coolant line; a second coolant line fluidicallycoupled to said first coolant line at a first end and a second endwherein said first coolant line and said second coolant line form acontinuous closed loop; a third coolant line fluidically coupled to saidfirst coolant line and said second coolant line, wherein said firstcoolant line, said second coolant line and said third coolant line forma continuous closed loop; a quantity of coolant contained within saidcontinuous closed loop; a radiator fluidically coupled to said secondcoolant line between said first end and said second end; a water pumpfluidically coupled within said first coolant line and rotatably coupledto said engine; a water motor fluidically coupled to said second coolantline between said first end and said second end; a fan coupled to saidwater motor, said fan rotating to cool said radiator and said condenseras a function of the flow rate of said quantity of coolant through saidwater motor; a valve fluidically coupled to said second coolant line andto said third coolant line, said valve having a first open position, asecond open position and a closed position, wherein said valve movesfrom either said first open position or said closed position to saidsecond open position when said pilot pressure within the compressorreaches a threshold pressure level after the air-conditioner isactuated; a pump control coupling coupled to said pump, said pumpcontrol coupling controlling the rotational rate of said water pump andsaid water pump impellers to pump said quantity of coolant through saidsecond coolant line; a belt coupled to said crankshaft pulley and saidpump control coupling; at least one temperature sensor capable ofmeasuring engine operating temperature; and a controller electricallycoupled to said valve, said speed control coupling, said at least onetemperature sensor and the air-conditioning unit; (b) determining anengine operating temperature at the current engine speed using said atleast one temperature sensor; (c) determining a desired operatingtemperature for the engine at the current engine speed; and (d)controlling the actuation of said valve between said second openposition and said first open position to change said engine operatingtemperature to said desired operating temperature at the current enginespeed.
 13. The method of claim 11, wherein (d) further comprisescontrolling the rotational rate of said speed control coupling usingsaid controller to change said engine operating temperature to saiddesired operating temperature at the current engine speed.
 14. Themethod of claim 11, wherein (d) controlling the actuation comprises (d)decreasing said engine operating temperature to said desired operatingtemperature by actuating said valve from said second open position tosaid first open position to allow coolant to flow through said secondcoolant line.
 15. The method of claim 14, further comprising increasingthe rotational rate of said speed control coupling.
 16. The method ofclaim 13, wherein (d) controlling the actuation comprises: (d)decreasing said engine-operating temperature to said desired operatingtemperature by actuating said valve to said open position to allowcoolant to flow through said second coolant line; and increasing therotational rate of said speed control coupling at the current enginespeed.
 17. The method of claim 13, wherein (d) controlling the actuationcomprises: (d) increasing the engine-operating temperature to saiddesired operating temperature by maintaining said valve in said secondopen position to allow coolant to bypass said second coolant linebetween said valve and said second end.
 18. A method for controlling thetemperature of an engine at a current engine speed, the methodcomprising: (a) providing a cooling system comprising: a first coolantline coupled to the engine; a heater element coupled to said firstcoolant line; a second coolant line fluidically coupled to said firstcoolant line at a first end and a second end; wherein said first coolantline and said second coolant line form a continuous closed loop; aquantity of coolant contained within said continuous closed loop; aradiator fluidically coupled to said second coolant line between saidfirst end and said second end; a dual stage water pump fluidicallycoupled within said first coolant line and rotatably coupled to saidengine, said dual stage pump comprising a pair of independently actuatedpumps; a water motor fluidically coupled to said second coolant linebetween said first end and said second end; a fan coupled to said watermotor, said fan rotating to cool said radiator as a function of the flowrate of said quantity of coolant through said water motor; a valvefluidically coupled to said second coolant line, said valve having anopen position and a closed position; a pump control coupling coupled tosaid pump, said pump control coupling controlling the rotational rate ofsaid water pump and said water pump impellers to pump said quantity ofcoolant through said second coolant line; a belt coupled to saidcrankshaft pulley and said pump control coupling; at least onetemperature sensor capable of measuring engine operating temperature;and a controller electrically coupled to said valve, said speed controlcoupling, said at least one temperature sensor, and to each of said pairof individually actuated pumps comprising said dual stage water pump;(b) determining an engine operating temperature at the current enginespeed using said at least one temperature sensor; (c) determining adesired operating temperature for the engine at the current enginespeed; (d) controlling the actuation of said valve between said closedposition and said first open position to change said engine operatingtemperature to said desired operating temperature at the current enginespeed; (e) controlling the rotational rate of said speed controlcoupling using said controller to change said engine operatingtemperature to said desired operating temperature at the current enginespeed; and (f) controlling the actuation of said dual stage water pumpusing said controller to change said engine operating temperature tosaid desired operating temperature at the current engine speed.
 19. Themethod of claim 18, wherein (d) controlling the actuation comprises (d)decreasing said engine operating temperature to said desired operatingtemperature by actuating said valve to said open position using saidcontroller, therein allowing said quantity of coolant to flow throughsaid second coolant line.
 20. The method of claim 19, wherein (e)controlling the actuation comprises (e) decreasing said engine operatingtemperature to said desired operating temperature by increasing therotational rate of said speed control coupling.
 21. The method of claim19, wherein (f) controlling the actuation of said dual stage water pumpcomprises (f) decreasing said engine operating temperature to saiddesired operating temperature by actuating at least one of said pair ofindependently actuated pumps.
 22. The method of claim 19, wherein (f)controlling the actuation of said dual stage water pump comprises (f)decreasing said engine operating temperature to said desired operatingtemperature by actuating each of said pair of independently actuatedpumps.
 23. The method of claim 18, wherein (d) controlling the actuationcomprises (d) increasing said engine operating temperature to saiddesired operating temperature by actuating said valve to said closedposition using said controller, therein preventing said quantity ofcoolant to flow through said second coolant line.
 24. The method ofclaim 23, wherein (e) controlling the actuation comprises (e) increasingsaid engine operating temperature to said desired operating temperatureby increasing the rotational rate of said speed control coupling. 25.The method of claim 23, wherein (f) controlling the actuation of saiddual stage water pump comprises (f) increasing said engine operatingtemperature to said desired operating temperature by actuating at leastone of said pair of independently actuated pumps.
 26. The method ofclaim 23, wherein (f) controlling the actuation of said dual stage waterpump comprises (f) increasing said engine operating temperature to saiddesired operating temperature by actuating each of said pair ofindependently actuated pumps.
 27. The method of claim 18, wherein saidwater motor comprises a dual stage water motor electrically coupled tosaid controller, said dual stage water motor comprising a pair ofindependently actuated water motors.
 28. The method of claim 27, wherein(d) controlling the actuation comprises (d) decreasing said engineoperating temperature to said desired operating temperature by actuatingsaid valve to said open position using said controller, therein allowingsaid quantity of coolant to flow through said second coolant line. 29.The method of claim 28, wherein (e) controlling the actuation comprises(e) decreasing said engine operating temperature to said desiredoperating temperature by increasing the rotational rate of said speedcontrol coupling.
 30. The method of claim 28, wherein (f) controllingthe actuation of said dual stage water pump comprises (f) decreasingsaid engine operating temperature to said desired operating temperatureby actuating at least one of said pair of independently actuated pumps.31. The method of claim 28, wherein (f) controlling the actuation ofsaid dual stage water pump comprises (f) decreasing said engineoperating temperature to said desired operating temperature by actuatingeach of said pair of independently actuated pumps.
 32. The method ofclaim 28, further comprising: (g) decreasing said engine-operatingtemperature to said desired temperature by actuating at least one ofsaid pair of independently actuated water motors.
 33. The method ofclaim 28, further comprising: (g) decreasing said engine-operatingtemperature to said desired temperature by actuating each of said pairof independently actuated water motors.
 34. The method of claim 33,wherein (f) controlling the actuation of said dual stage water pumpcomprises (f) decreasing said engine operating temperature to saiddesired operating temperature by actuating at least one of said pair ofindependently actuated pumps.
 35. The method of claim 33, wherein (f)controlling the actuation of said dual stage water pump comprises (f)decreasing said engine operating temperature to said desired operatingtemperature by actuating each of said pair of independently actuatedpumps.
 36. The method of claim 27, wherein (d) controlling the actuationcomprises (d) increasing said engine operating temperature to saiddesired operating temperature by actuating said valve to said closedposition using said controller, therein preventing said quantity ofcoolant to flow through said second coolant line.
 37. The method ofclaim 36, wherein (e) controlling the actuation comprises (e) increasingsaid engine operating temperature to said desired operating temperatureby increasing the rotational rate of said speed control coupling. 38.The method of claim 36, wherein (f) controlling the actuation of saiddual stage water pump comprises (f) increasing said engine operatingtemperature to said desired operating temperature by actuating at leastone of said pair of independently actuated pumps.
 39. The method ofclaim 36, wherein (f) controlling the actuation of said dual stage waterpump comprises (f) increasing said engine operating temperature to saiddesired operating temperature by actuating each of said pair ofindependently actuated pumps.
 40. A method for controlling thetemperature of an engine at a current engine speed, the methodcomprising: (a) providing a cooling system comprising: a first coolantline coupled to the engine; a heater element coupled to said firstcoolant line; a second coolant line fluidically coupled to said firstcoolant line at a first end and a second end; wherein said first coolantline and said second coolant line form a continuous closed loop; aquantity of coolant contained within said continuous closed loop; aradiator fluidically coupled to said second coolant line between saidfirst end and said second end; a water pump fluidically coupled withinsaid first coolant line and rotatably coupled to said engine; a dualstage water motor fluidically coupled to said second coolant linebetween said first end and said second end, said dual stage water motorcomprising a pair of independently actuated water motors; a fan coupledto said dual stage water motor, said fan rotating to cool said radiatoras a function of the flow rate of said quantity of coolant through saidpair of independently actuated water motors; a valve fluidically coupledto said second coolant line, said valve having an open position and aclosed position; a pump control coupling coupled to said pump, said pumpcontrol coupling controlling the rotational rate of said water pump andsaid water pump impellers to pump said quantity of coolant through saidsecond coolant line; a belt coupled to said crankshaft pulley and saidpump control coupling; at least one temperature sensor capable ofmeasuring engine operating temperature; and a controller electricallycoupled to said valve, said speed control coupling, said at least onetemperature sensor, and to each of said pair of individually actuatedpumps comprising said dual stage water pump; (b) determining an engineoperating temperature at the current engine speed using said at leastone temperature sensor; (c) determining a desired operating temperaturefor the engine at the current engine speed; (d) controlling theactuation of said valve between said closed position and said first openposition to change said engine operating temperature to said desiredoperating temperature at the current engine speed; (e) controlling therotational rate of said speed control coupling using said controller tochange said engine operating temperature to said desired operatingtemperature at the current engine speed; (f) controlling the actuationof said water pump using said controller to change said engine operatingtemperature to said desired operating temperature at the current enginespeed; and (g) controlling said engine-operating temperature to saiddesired temperature by actuating at least one of said pair ofindependently actuated water motors.
 41. The method of claim 40, wherein(d) controlling the actuation comprises (d) decreasing said engineoperating temperature to said desired operating temperature by actuatingsaid valve to said open position using said controller, therein allowingsaid quantity of coolant to flow through said second coolant line. 42.The method of claim 40, wherein (e) controlling the actuation comprises(e) decreasing said engine operating temperature to said desiredoperating temperature by increasing the rotational rate of said speedcontrol coupling.
 43. The method of claim 40, wherein (d) controllingthe actuation comprises (d) increasing said engine operating temperatureto said desired operating temperature by actuating said valve to saidclosed position using said controller, therein preventing said quantityof coolant to flow through said second coolant line.
 44. The method ofclaim 43, wherein (e) controlling the actuation comprises (e) increasingsaid engine operating temperature to said desired operating temperatureby increasing the rotational rate of said speed control coupling. 45.The method of claim 40, wherein (d) controlling the actuation comprises(d) decreasing said engine operating temperature to said desiredoperating temperature by actuating said valve to said open positionusing said controller, therein allowing said quantity of coolant to flowthrough said second coolant line.
 46. The method of claim 40, wherein(e) controlling the actuation comprises (e) decreasing said engineoperating temperature to said desired operating temperature byincreasing the rotational rate of said speed control coupling.
 47. Themethod of claim 40, wherein (g) controlling said engine-operatingtemperature to said desired temperature by actuating at least one ofsaid pair of independently actuated water motors comprises: (g)decreasing said engine-operating temperature to said desired temperatureby actuating each of said pair of independently actuated water motors.48. The method of claim 40, wherein (d) controlling the actuationcomprises (d) increasing said engine operating temperature to saiddesired operating temperature by actuating said valve to said closedposition using said controller, therein preventing said quantity ofcoolant to flow through said second coolant line.
 49. The method ofclaim 48, wherein (e) controlling the actuation comprises (e) increasingsaid engine operating temperature to said desired operating temperatureby increasing the rotational rate of said speed control coupling.